32 6 Eggs of the fmall Erejh- Water Snail , 
is then a moft agreeable and amazing Spedla-? 
cle, fhewing itfelf very diftin&ly, and re-* 
fembling a little oblong Bladder, much lefs 
a$ one End than the other: the Pulfation 
proceeds under the Eye with great Exactnefs 
and Regularity, and the Syftole and Diaftole 
of this Veffel are nearly equal to thole of 
the human Heart, fomewhat more than fixr 
ty Pulfations being performed in a Minute, 
as I have found by feveral Trials, keeping 
my Finger at the fame Time on my own 
Pulfe, which ufually beats two or three 
Strokes more. The Heart is large in Pro- 
portion, dnd may be always feen, until the 
Animal increafmg in Bulk and becoming 
Confequently more opake, in fome Portions 
it hardly can be perceived : but as the Ani¬ 
mal frequently turns itfelf within the Egg, 
a little Patience will bring the Heart in full 
View again ; and that as-long as the Embrio 
continues within the Egg. Nay, even after 
it is hatched, the Heart may be difcoverecj 
for fome days through the tranfparent 
Shell 
The general Plan of Nature is fo uniform, 
in the Production of living Animals, though 
with fome little Variations as to the Man¬ 
ner of its Execution, that from what we are 
able to difcpver in the very tranfparent Eggs 
* The fame progreffion I have been defcribing, was ob~ 
lerved at Norwich, by Mr. drderon, in the Cornu. Jmmonis 
Eiver Snail. 
